As the title states, the 960 makes noise from under the hood when warm and under higher rev and load conditions. When cold and when idling warm, it is perfectly quiet.
Am I missing something? Could it not even be the power steering?

Have no idea what that could be. I do know, however, that my power steering pump on my 97' 960 was wailing this past winter upon startup and until it got warm. Then it quieted down. Might still be your pump, just different symptoms than what I had. Good luck in finding it. I can imagine it can be quite unnerving especially under load.